Thirty years after World War II ended, a relaxation of British Government security strictures brought to light one of its most important secrets. It was revealed, to understandable astonishment, that the war had been won not just by military genius or by the dogged courage of the Allied Armed Forces though both had of course been of vast significance – but by groups of obscure or unknown people who found out in advance what the enemy intended to do, and passed on this knowledge to those who commanded the armies, the fleets and the bomber formations. Vital information that turned the tide of battle in the North African desert or on the Pacific Ocean proved to have been obtained not by the skill and bravery of spies, or by miraculous coincidence, but by the plodding and unglamorous work of operatives who read the enemy’s coded messages. The result has been, of necessity, a re-evaluation of reputations and a rewriting of history.
The ability to gain access to the very thought processes of the enemy was a major epic of ingenuity, and a great adventure. What makes it even more remarkable is the fact that the people who carried it out (and there were thousands of them) received no public recognition for their contribution to the war effort, and were forbidden to tell even their families what they had been doing throughout the long years of conflict. Without a single known exception, they faithfully kept this silence until, an entire generation later, they were permitted by the government to admit their involvement. The story of these cryptographers has considerable bearing on our own postwar world, for in the process of breaking the secret codes of Nazi Germany they created the computer as we know it today.
The breaking of German codes began long before the start of war in 1939. For almost a decade, cryptanalysts in Poland had studied and replicated the Enigma machine, which was used by German armies from the 1920s until Hitler’s defeat. Thanks to their skill and perseverance the Western democracies, France and Britain, were in possession of working copies of Enigma by the time hostilities began. Though Poland itself was dismembered and conquered, it was thus able to make a contribution to eventual victory that was beyond calculation.
As for the Axis powers, it was fortunate that they took a view of cryptography that was both disdainful and complacent. By tradition, the German military mind did not approve of, or appreciate, such skulduggery. Throughout the war, senior officers therefore sometimes ignored opportunities to make use of intelligence that could have been of value. They also largely took it for granted that their communications were secure, and left it at that.
Their greatest disadvantage of all, however, was the nature of Adolf Hitler. Having grown accustomed to a sense of his own infallibility, the Fiihrer saw no need to waste time or effort on cryptanalysis, and with few exceptions he failed to take it seriously. He had, after all, conquered Europe by relying on his own hunches. Swift and decisive action, not painstaking intelligence gathering, was the key to success. Hitler’s entourage, and his General Staff, could not have retained their positions without sharing, at least publicly, this belief in his genius and thus by implication regarding intelligence as unnecessary. The Fiihrer was provided, by several organizations, with a great many decrypted Allied messages. These were often highly informative. Hitler, however, committed a classic error by failing to read them objectively. His mind already made up, he would dismiss data that did not fit with his views. He once scrawled across a dossier dealing with Soviet economic recovery the comment: ‘This cannot be.’ It probably did not, in any case, help the